Bean curd containing lactic fermenting bacteria culture fluid and a method for preparing the same, and beverage containing the same

ABSTRACT

The present invention relates to a method for preparing bean curd using lactic acid bacteria culture, and to a lactic acid beverage, and to a method for preparing the same. Specifically, the present invention provides a method for preparing bean curd containing lactic acid by preparing bean soup using soybeans, cooling the bean soup and adding lactic acid bacteria culture to the bean soup, and the bean curd prepared according to the method, and a method for preparing a lactic acid beverage by adding syrup or fruit juice to the bean soup remaining after preparing the bean curd, and the lactic acid beverage prepared according to the method.

The present patent application is a non-provisional application ofInternational Application No. PCT/KR00/01461, filed Dec. 14, 2000.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a method for preparing bean curdcontaining lactic acid bacteria culture, and to bean curd preparedaccording to the method, to a beverage containing lactic acid bacteria,and to a method for preparing the same. Specifically, the presentinvention relates to a method for preparing bean curd containing lacticacid bacteria by adding lactic acid bacteria culture to bean soup, andbean curd prepared according to the method, a method for preparing abeverage containing lactic acid using bean soup remaining afterpreparing the bean curd, and a beverage containing lactic acid preparedaccording to the method.

(b) Description of the Related Art

Proteins separated from beans can be denatured from soluble proteins tonon-soluble proteins according to the concentration of salts, and thesenon-soluble proteins are compressed to make a bean curd that is loved byOrientals. In addition, positive health effects from foods made withbeans, such as bean curd, have been newly found.

Beans are known to have anticancer effects due to lecithin, and tocontain other healthful ingredients. For examples, an anticancer drugand a hypotensive are separated from soybean paste made from beans, andbean sprouts contain asparagine which protects the liver from hangovers.

However, bean curds are conventionally prepared using brine, and a newpreparation method of bean curds has not been developed from theconventional method. Brine is a by-product obtained when sea saltabsorbs moisture in the air due to its deliquescence property todissolve and wash away ingredients other than the salts, over a longperiod of time. Accordingly, brine comprises various dissolvedingredients which are contained in sea water, including cations such asmagnesium that are known to play an important role in making bean curds.

A deficiency in magnesium causes serious health problems since magnesiumions are physiologically important, but a high intake thereof can alsocause physical problems. In addition, unpurified salts generate a bittertaste due to magnesium ions.

Accordingly, it can be predicted that the magnesium intake of Koreansexceeds a sufficient amount since bean curds made using brine arepresently sold on the market, and unpurified salts are used in homes.Although the amount of magnesium intake from bean curds is not excessivebecause the amount of magnesium remaining in bean curds is not large,since Koreans habitually use sauces including fermented soybeans,considering the amount of magnesium contained in sauces, they consume anexcessive amount of magnesium and are consequently attacked by relateddiseases of adults.

In addition, the taste of bean curds can be good while they are hot, butit cannot be preserved for a long time even if stored cold.

Particularly, bean curds are difficult to preserve for even one daywithout refrigeration, and microorganisms can grow under conditions inwhich constituents other than protein contained in beans remain even intrace amounts. However, there is no remedy for these problems.

Bean curds containing lactic acid are presently sold on the market, andKorean Patent Application No. 98-1089 discloses a method for preparingbean curds by lactic acid fermentation. However, according to themethod, lactic acid is fermented and aged in soybeans to prepare beancurds containing lactic acid, and the method has a disadvantage in thatmanufacturing costs are high because it uses expensive diary productssuch as milk as well as beans, etc. as raw materials.

SUMMARY OF THE INVENTION

The present invention is made to solve these problems, and it is anobject of the present invention to provide a method for preparing beancurds by using lactic acid bacteria culture, and to provide bean curdsprepared according to the method. According to the method of the presentinvention, bean curds are prepared using lactic acid bacteria culturethereby eliminating factors hazardous to health, the lactic acid inlactic acid fermenting foods such as Kimchi is used thereby decreasingmanufacturing costs, and the growth of Gram negative bacteria isinhibited due to lactic acid and lactic acid bacteria, therebyincreasing storage properties and microbiological safety of bean curds.

It is another object of the present invention to provide a method forpreparing a beverage containing lactic acid using bean soup remainingafter preparing bean curds according to the above method, and to providea beverage containing lactic acid prepared according to the method.

In order to achieve these objects, the present invention provides amethod for preparing bean curds by adding lactic acid bacteria culturecomprising the steps of:

a) preparing lactic acid bacteria culture by fermenting i) salt, sugar,water and ii) material which is one or more selected from a groupconsisting of vegetables, fruits, and a mixture thereof with lactic acidbacteria;

b) preparing the bean soup by pulverizing the soaked soybeans in water,heating, and filtering; and

c) adding the lactic acid bacteria culture of step a) to the been soupcooled at 40° C.

In addition, the present invention provides bean curds preparedaccording to the method.

Specifically, the bean curds prepared according to the present inventioncomprises living lactic acid bacteria that increases the preservationproperty of bean curds compared to conventional bean curds, and alsoincreases probability that lactic acid reaches the intestine when thebean curds are digested to increase intestine-cleaning effects.

The lactic acid bacteria culture is preferably prepared by mixing one ormore of vegetables, fruits and mushrooms at room temperature usingpurified water such as tapped water in a basic medium comprising 2.5%salts and 1% sugar. Although the lactic acid bacteria can be prepared atroom temperature without sterilization, sterilizing and asepticoperation should be preceded with for commercial production.

Favorable lactic acid bacteria existing in Kimchi are found in thelactic acid bacteria culture prepared as the above.

Any vegetables including radishes, cabbages, etc. can be used as thevegetables, and any fruit including pears, pineapples, etc. can be usedas the fruits.

In addition, bean curd dregs which is solid components produced afterfiltering heated soybeans, can be added to one material or more selectedfrom vegetables, fruits, and mushrooms. Specifically, the bean curddregs can be utilized as good nitrogen and carbon sources when culturinglactic acid bacteria, because they are pulverized beans and can befurther decomposed using microorganism enzymes. The bean curd dregs canbe a substitute for medium for culturing the lactic acid, it cuts downthe production cost.

Lactic acid bacteria have a property of inhibiting the growths ofdisease-causing bacteria and harmful bacteria because of the lactic acidproduced by lactic acid fermentation, and they are used as a medicinefor intestinal disorders because they inhabit the intestine to preventabnormal fermentation of various bacteria. In addition, they are Grampositive and are common anaerobic or anaerobic bacteria, they have nomotility, most are catalase negative, and they require various vitamins,amino acids, peptides, etc. for their growth. These lactic acid bacteriaare largely classified into lactic acid bacillus and lactic acidmicrococcus.

The representative example of the lactic acid bacillus is lactic acidbacteria pertaining to the genus Lactobacillus, which are aerobic lacticacid bacteria existing in the intestine of all mammals and in otheranimals, and are used to treat autopoisoning of the intestine.

The lactic acid micrococcus is further classified into the generaStreptococcus, Pediococcus and Leuconostoc, the lactic acid bacteriapertaining to the genus Pediococcus is streptococcus, and P. pentosaceusis mainly found in Kimchi. In addition, lactic acid bacteria pertainingto the genus Leuconostoc are diplococcus and L. mesenteroides produce alot of gluten-like substance from sugar.

In the present invention, lactic acid bacteria pertaining to the genusLeuconostoc are preferably produced, because they are found in lacticacid fermenting foods such as Kimchi, they produce a similar amount oflactic acid as lactic acid bacteria pertaining to other genera and theyare inexpensive.

The degree of lactic acid production decreases to pH 5.0 or lower within48 hours after fermentation in the case of natural fermentation, therebyinhibiting the growth of non-acid resistant bacteria. Lactic acidbacteria culture undergoing sufficient lactic acid production for 72hours or more is preferably used. Other lactic acid bacteria can be usedto prepare bean curd by controlling growth conditions when preparinglactic acid bacteria culture.

The preferable lactic acid bacteria culture is from Kimchi.

In addition, bean curd is conventionally prepared in hot conditions byboiling bean soup, while in the present invention, lactic acid bacteriaculture is added to bean soup after the bean soup is cooled so that thebean curd contains living lactic acid bacteria. Thus, even when cookedat high temperature, although lactic acid bacteria cannot survive, theeffect of the lactic acid intake lasts and adult disease prevention andintestine cleaning effects are shown, and the bean curd preservingeffect is still shown until that point.

The temperature to which to cool the bean soup is preferably 40° C. orless.

Conventionally, in order to prepare bean curd, raw material soybeans arecarefully selected and adulterants other than soybeans are removed.After selection, the soybeans are washed well and soaked in water tosufficiently absorb water. At this point, the weight of the soybeansincreases by approximately 2.2 to 2.3 times. The soybeans are pulverizedwhile absorbing water, and the pulverized soybeans are heated toapproximately 100° C. using sour milk neutralized with Ca(OH)₂ orsilicon resin as a deformer. The heated pulverized soybeans are filteredto obtain bean soup, and the bean soup is coagulated at 70 to 75° C.using brine or CaCl₂, etc., while stirring, to obtain bean curd. In thepresent invention, after coagulating the bean soup at 70 to 75° C., theheated pulverized soybeans are cooled, and lactic acid bacteria cultureis added to the cooled soybeans without using brine or CaCl₂ tocoagulate the bean soup, thereby preparing bean curd comprising lacticacid bacteria.

The present invention also provides a method for preparing a beveragecontaining lactic acid bacteria as the above by mixing bean soupremaining after preparing bean curd using the lactic acid bacteriaculture with syrup or fruit juice.

For example of the present invention, a beverage containing lactic acidbacteria as the above comprising the steps of:

a) preparing lactic acid bacteria culture by fermenting i) salt, sugar,water and ii) material which is one or more selected from a groupconsisting of vegetables, fruits, and a mixture thereof with lactic acidbacteria;

b) preparing the bean soup by pulverizing the soaked soy bean in water,heating and filtering;

c) adding the lactic acid bacteria culture of step a) o the bean soupcooled at 40° C.; and

d) mixing syrup or fruit juice with the bean soup remaining afterpreparing bean curds of step c).

The present invention also provides a lactic acid beverage.

The bean soup remaining after preparing bean curd contains variousorganic substances such as amino acids, vitamins, fiber, etc., inorganicsalts and important lactic acid bacteria. Thus a healthy lactic acidbeverage can be prepared by adding additives containing appropriatefavors such as syrup or fruit juice, etc. to the bean soup.

Accordingly, as shown in FIG. 1, lactic acid bean curd can be preparedby preparing bean soup using soybeans, cooling it at 40° C. andintroducing lactic acid bacteria culture into the cooled bean soup, andit can also be prepared by preparing lactic acid bacteria culture usingbean dregs remaining after preparing bean soup and introducing thelactic acid bacteria culture into the cooled bean soup. Also, lacticacid beverage can be prepared by adding additives such as syrup andfruit juice to the bean dregs remaining after preparing bean curd.

In addition, the present invention can be prepared bean curd adding thelactic acid bacteria culture, and prepared bean curd adding organicacid.

For example of the present invention, a bean curd as the abovecomprising the steps of:

a) soaking soybeans in water;

b) pulverizing the soaked soybeans of step a);

c) heating the pulverized soybeans of step b) using a deformer;

d) filtering the heated pulverized soybeans of step c) to prepare beansoup; and

e) cooling at 40° C. the bean soup of step d) and adding lactic acidthereto.

The organic acid is preferably lactic acid or acetic acid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a process chart for preparing lactic acid bean curd and alactic acid beverage according to one embodiment of the presentinvention.

DETAILED DESCRIPTION AND THE PREFERRED EMBODIMENTS

The present invention will now be explained with reference to thefollowing Examples. However, these are to illustrate the presentinvention and the present invention is not limited to them.

EXAMPLES 1-7

50 g of cabbage, 60 g of garlic, 100 g of pear, 40 g of unripe hotpeppers, 65 g of pineapple, 10 g of potatoes and 75 g of radish wereweighed and introduced into each 360 mL bottles. A mixture of salts andsugar was prepared by mixing 100 g of salts, 40 g of sugar, and watersuch that the mixture reached 4 L. 330, 337, 301, 347, 337, 290 and 284mL of the mixture were respectively introduced into each bottle, and thebottles were left to stand at room temperature for 3 days.

The pH of the lactic acid bacteria culture prepared according to theExamples 1-7 was 3.5.

Comparative Example 1

The solution was prepared by mixing salts, sugar and water. The pH ofthe solution was 6.0.

EXAMPLES 8-14

Bean curds for Examples 8 to 14 were prepared by adding 3 mL of soybeanmilk (Samyook soybean milk) to 2 mL of the lactic acid bacteria cultureprepared for each of Examples 1 to 7.

EXAMPLE 15

Bean curd was prepared by adding 3 mL of soybean milk (Samyook soybeanmilk) to 2 mL of vinegar (Double Strength Apple Vinegar, from Otugi FoodCompany).

Comparative Example 2

Bean curd was prepared by adding 3 mL of soybean milk to 2 mL of thesolution of Comparative Example 1.

Comparative Example 3

Bean curd was prepared by the same method as in Comparative Example 2,except that only soybean milk was used, with no solution.

The results are presented in the following Table 1.

TABLE 1 Coagulation Example 8 ◯ Example 9 ◯ Example 10 ◯ Example 11 ◯Example 12 ◯ Example 13 ◯ Example 14 ◯ Example 15 ◯ Comparative Example2 X Comparative Example 3 X

As can be seen from the Table 1, in Examples 8 to 14 according to thepresent invention, soybean milk was coagulated after the lactic acidbacteria culture was introduced to prepare bean curd, while, and it didso quickly, while in Comparative Examples 2 and 3 where the lactic acidbacteria culture was not introduced, soybean milk was not coagulated.Particularly, in the case when radish was used, soybean milk was mostrapidly coagulated to prepare bean curd. In addition, even when organicacid such as vinegar was directly added during the bean curd preparingprocess, soybean milk was coagulated, which indicates that bean curd canbe prepared using organic acid.

The present invention uses fermented lactic acid bacteria culture toprepare bean curd, thereby standardizing a bean curd preparation method,and prepares bean curd and a beverage containing lactic acid withimproved preservation properties and increases lactic acid intakethereby improving peoples' health.

In addition, the present invention prepares lactic acid containing beancurd and a beverage by fermenting lactic acid bacteria culture usingbean curd dregs that are by-product produced when preparing bean curdand introducing it during the bean curd preparation process, therebydecreasing preparation costs of bean curd and lactic acid beverages andproviding bean curd and a beverage rich in lactic acid.

What is claimed is:
 1. A method for preparing bean curd comprising thesteps of: a) preparing a lactic acid bacteria culture by fermenting i)salt, sugar, water and ii) material which is one or more selected fromthe group consisting of cabbage, radish, pear, pineapple and a mixturethereof with lactic acid bacteria; b) preparing a bean soup bypulverizing soy beans soaked in water, heating, and filtering; and c)adding the lactic acid bacteria culture of step a) to the bean soup,thereby forming a bean curd.
 2. The method for preparing bean curdaccording to claim 1, wherein the lactic acid bacteria culture of stepa) is lactic acid bacteria existing in Kimchi.
 3. A bean curd preparedaccording to the method of claim
 1. 4. A method for preparing beveragecontaining lactic acid bacteria comprising the steps of: a) preparinglactic acid bacteria culture by fermenting i) salt, sugar, water and ii)material which is one or more selected from the group consisting ofcabbage, radish, pear, pineapple and a mixture thereof with lactic acidbacteria; b) preparing a bean soup by pulverizing soy beans soaked inwater, heating, and filtering; and c) adding the lactic acid bacteriaculture of step a) to the bean soup to prepare bean curd; d) separatingthe bean soup remaining from the bean curd; and e) mixing syrup or fruitjuice with the remaining bean soup.
 5. Beverage prepared according toclaim
 4. 6. A method for preparing bean curd according to claim 1,wherein the bean soup is cooled at 40° C.
 7. A method for preparingbeverage containing lactic acid bacteria according to claim 4, whereinthe bean soup is cooled at 40° C.